1. Field of the Invention
The present invention relates to an apparatus in a photographic printer that indicates the relative position of a selected film frame at a print gate aperture with respect to other film frames of a disc-like film unit.
2. Description of the Prior Art
Apparatus for indicating what film frame conventional strip film is positioned at the point gate aperture of a photographic printer are well known in the art. However, this type of apparatus is wholly unsuited for indicating a particular film frame in a disc-like film unit at a point gate wherein the individual image frames are located circumferentially about a central hub. Examples of a disc film unit are disclosed in the following U.S. patents:
______________________________________ Inventor U.S. Pat. No. ______________________________________ Sethi 4,194,822 Morse 4,208,116 Harvey et al 4,208,117 Sethi et al 4,212,673 Harvey et al 4,255,034 Harvey 4.264,169 Harvey et al 4,268,145 ______________________________________
A print gate indexing device for a disc-like film unit is disclosed in Research Disclosure of August, 1978, Disclosure No. 17287. Using a print gate indexing device, each image frame is manually advanced to the print gate. The disc-like film unit is held in a single horizontal plane while selected image frames are rotationally indexed to the print gate. Since the indexing of individual film frames to the print gate aperture is essentially manual, no indicator is shown to indicate what particular film frame is at the print gate aperture.
A rotational positioning device is also disclosed in Research Disclosure of August, 1978, Disclosure No. 17289. The rotational positioning device includes an assembly from which a central shaft extends upwardly for coaxially centering the disc-like film unit on the assembly. A pair of pins also extend upward from the assembly for extending through cooperating apertures in the hub of the disc film unit. No apparatus for indicating what selected film frame is positioned at the print gate aperture is shown.
The Clifton et al U.S. Pat. No. 4,203,664 illustrates a ratchet assembly used to position a disc film unit. A pneumatically operated drive pawl is provided for driving a ratchet gear. A film frame viewer is provided for viewing and classifying individual film frames prior to printing. No indicator is provided to indicate which film frame is presently at the film gate aperture.
The Modney et al U.S. Pat. No. 4,202,733 shows a wheel beneath the disc film unit holder having a plurality of notches corresponding to the number of frames in a disc film unit. A pair of diametrically opposed blocks containing ball plungers engage a pair of diametrically opposed notches in the wheel when the balls and notches are aligned. The wheel is allowed to rotate, thereby indexing individual film frames, when the balls are withdrawn from the notches, permitting the wheel to freely rotate. Again, a film frame viewer is provided for viewing individual film frames prior to printing and no indicator is provided to indicate which film frame is presently at the film gate aperture.